The invention concerns a process for producing a high-resolution surface pattern on a substrate, wherein, in the process, a printing substance is applied to the substrate in pattern form by means of a printing process. The invention further concerns a multi-layer body with a pattern layer applied to a substrate layer in pattern form by means of a printing process, and an apparatus for producing a high-resolution surface pattern which includes a printing station for applying a viscous printing substance to a substrate in pattern form.
Intaglio, offset, relief and screen printing processes are usually employed for applying a printing substance to a substrate.
Intaglio printing denotes a printing process using printing elements which are recessed with respect to the surface of the printing form. After complete inking of the printing form the surface is freed of the printing ink so that the ink only remains behind in the recessed locations. The nature of the inking operation and the operation of wiping the surface clear of ink do not permit pure printing over an area so that entire drawings are resolved into lines, dots and picture elements. Because of the differing depth and size of the individual printing elements they accommodate more or less printing ink and consequently the print produced involves different colouring power at the various locations in the image.
In order to improve the resolution of those printing processes DE 37 05 988 A1 proposes using as the printing form a homogeneous sheet or film into which items of printing information are introduced by means of very fine perforating processes, in the form of capillaries, as printing passages. A low-viscosity printing substance is introduced into the capillaries and the printing substance is applied to the article or material to be printed upon from the capillaries with a defined pressing force, in the form of very fine print. In that respect, focused laser beams of a beam diameter of 1 to 10 μm are used for producing the very fine perforations. The printing form employed is a homogeneous film or sheet which is 20 to 50 μm in thickness, for example a plastic or metal film or sheet.
DE 195 44 099 A1 proposes using a transparent cylinder as the ink or printing carrier, the cylinder being provided with cups which bear directly against each other. The cups are filled with molten ink and then the ink is put into a solid condition by thermal effect.
DE 197 46 174 C1 proposes a procedure in which a fluid, meniscus-forming printing substance is continuously introduced into cups and the printing substance in the cups is transferred by means of a process induced by an energy-producing device, on an item or material to be printed upon, which is moved towards the cups.
Accordingly, in the above-described known processes for improving the resolution which can be achieved by means of a printing process, the attempt is made to improve the level of resolution which can be achieved by applying, with the highest possible degree of spot accuracy, a minimum possible amount of printing substance.